Preheat oven to 425. Cut the whole pound of bacon in thirds (3 sections per slice) Use a glass (if you have it) 9x13 pan.
Wrap a piece of the bacon around the water chestnut and secure with a toothpick. For me it usually comes out about perfect, the ratio of bacon slices to water chestnuts...repeat process until you have no more water chestnuts or bacon whichever comes first.
In a small bowl combine the ketchup and brown sugar, making sure to get all the lumps out of the sugar and drizzle it over the water chestnuts, using all of the sauce.
Place in preheated oven and bake until very bubbly and bacon starts crisping on the edges real good. Approx. 20 minutes. Rove from oven and let cool slightly...they will be VERY HOT!! Serve warm...oh sooo good!!